Factbox-
The vast nuclear plant in the eye of the war in Ukraine
LONDON (Reuters) - The Zaporizhzhia nuclear power plant in southern Ukraine has been shelled in recent days, opening up the possibility of a grave accident just 500 km (around 300 miles) from the site of the world's worst nuclear accident, the 1986 Chernobyl disaster.
WHAT IS IT?
The Zaporizhzhia nuclear power plant has six Soviet-designed VVER-1000 V-320 water-cooled and water-moderated reactors containing Uranium 235, which has a half life of more than 700 million years.
It is Europe's biggest nuclear power plant and one of the biggest in the world. Construction began in 1980 and its sixth reactor was connected to the grid in 1995.
Pressurised water is used to transfer heat away from the reactor and to slow down neutrons to enable the Uranium 235 to continue its chain reaction.
If the water was cut, and auxiliary systems such as diesel generators failed to keep the reactor cool due to an attack, then the nuclear reaction would slow though the reactor would heat up very swiftly.
At such high temperatures, hydrogen could be released from the zirconium cladding and the reactor could start to melt down.
At least two reactors are still working at the plant.
WHAT ABOUT THE SPENT FUEL?
Besides the reactors, there is also a dry spent fuel storage facility at the site for used nuclear fuel assemblies, and spent fuel pools at each reactor site which are used to cool down the used nuclear fuel.
"The basins of spent fuel are just big pools with uranium fuel rods in them - they are really hot depending on how long they have been there," said Kate Brown, an environmental historian at the Massachusetts Institute of Technology whose book "Manual for Survival" documents the full scale of the Chernobyl disaster.
"If fresh water is not put in then the water will evaporate. Once the water evaporates then the zirconium cladding will heat up and it can catch on fire and then we have a bad situation - a fire of irradiated uranium which is very like the Chernobyl situation releasing a whole complex of radioactive isotopes."
An emission of hydrogen from a spent fuel pool caused an explosion at reactor 4 in the Fukushima nuclear disaster in 2011.
According to a 2017 Ukrainian submission to the IAEA, there were 3,354 spent fuel assemblies at the dry spent fuel facility and around 1,984 spent fuel assemblies in the pools.
That is a total of more than 2,200 tonnes of nuclear material excluding the reactors, according to the document https://www.iaea.org/sites/default/files/national_report_of_ukraine_for_the_6th_review_meeting_-_english.pdf.
WHO CONTROLS IT?
After invading Ukraine on Feb. 24, Russian forces took control of the plant in early March.
Ukrainian staff continue to operate it, but special Russian military units guard the facility and Russian nuclear specialists give advice.
If there was a nuclear accident, it is unclear who would deal with it during a war, said Brown.
"We don't know what happens in a wartime situation when we have a nuclear emergency," Brown said. "In 1986 everything was running as well as it ran in the Soviet Union so they could mobilise tens of thousands of people and equipment and emergency vehicles to the site."
"Who would be taking charge of that operation right now?"
WHAT HAS HAPPENED SO FAR?
The plant was struck in March but there was no radiation leak and the reactors were intact. Both Russia and Ukraine blamed each other for that strike.
In July, Russia said Ukraine had repeatedly struck the territory of the plant with drones and missiles. Pro-Ukrainian social media said "kamikaze drones" had struck Russian forces near the plant.
Reuters was unable to immediately verify battlefield accounts of either side.
- Aug. 5: The plant was shelled twice. Power lines were damaged. An area near the reactors was hit.
Russia said that Ukraine's 45th Artillery Brigade also struck the territory of the plant with 152-mm shells from the opposite side of the Dnipro river. Ukraine's state nuclear power company, Energoatom, said Russia fired at the plant with rocket-propelled grenades.
- Aug. 6: shelled again, possibly twice. An area next to the dry spent nuclear fuel storage facility was hit.
Energoatom said Russia fired rockets at the plant. The Russian forces said Ukraine struck it with a 220-mm Uragan rocket launcher.
- Aug. 7: shelled again
Russia said Ukraine's 44th Artillery Brigade struck the plant, damaging a high-voltage line. Russia's defence ministry said power at reactors 5 and 6 was reduced to 500 megawatts.
(Reporting by Guy Faulconbridge; Editing by Andrew Heavens)
EXPLAINER: Fighting in Ukraine endangers big nuclear plant
Ukrainian President Volodymyr Zelenskyy speaks at a news conference in Kyiv, Ukraine, on July 28, 2022. Ukrainian officials countered by accusing Russian forces of planting explosives at the Zaporizhzhia nuclear plant in preparation for an expected Ukrainian counteroffensive in the region. They also have accused Russia of launching attacks from the plant using Ukrainian workers there as human shields and shelling the place themselves. Ukrainian President Volodymyr Zelenskyy said that the Russian shelling and mining of the plant amount to "nuclear blackmail."
The Associated Press
Wed, August 10, 2022
Russia and Ukraine have accused each other of shelling Europe's largest nuclear power plant, stoking international fears of a catastrophe on the continent. A look at the plant and the situation around it:
EUROPE'S BIGGEST NUCLEAR PLANT
The Zaporizhzhia plant is in southern Ukraine, near the town of Enerhodar on the banks of the Dnieper River. It is one of the 10 biggest nuclear plants in the world.
Built during the Soviet era, it has six reactors with a total capacity of 5,700 megawatts. Three of the reactors are in operation.
Before the war, the plant accounted for about half of the electricity generated by nuclear power in Ukraine. The country has 15 reactors at four active plants, and also is home to the decommissioned Chernobyl plant, the site of the 1986 nuclear disaster.
RUSSIANS TAKE CONTROL
Russian troops overran the plant shortly after invading Ukraine on Feb. 24.
During the fighting in early March, Russian and Ukrainian forces exchanged fire near the plant. The skirmishes resulted in a fire at its training complex.
The Russians have left the Ukrainian staff in place to keep the plant operating, and it has continued to supply electricity to government-controlled parts of Ukraine.
The fighting around the plant has fueled fears of a disaster like the one at Chernobyl, where a reactor exploded and spewed deadly radiation, contaminating a vast area in the world's worst nuclear accident.
Russian forces occupied the heavily contaminated Chernobyl site soon after the invasion but handed control back to the Ukrainians after withdrawing from the area at the end of March.
RUSSIA AND UKRAINE TRADE ACCUSATIONS
Ukraine has accused Russia of storing troops and weapons at the plant and using its grounds to launch strikes against Ukrainian-controlled territory across the Dnieper. Ukrainian officials and military analysts say Moscow's forces have cynically employed the plant as a shield, knowing that the Ukrainians would be hesitant to fire back.
Russia has denied the accusations and, in turn, accused Ukrainian forces of repeatedly shelling the plant.
A series of attacks on the plant over the past few days has damaged some of its auxiliary equipment but not its reactors, and there has been no threat of a radiation leak, according to Russian authorities.
The Russian Defense Ministry said Ukrainian shelling of the plant on Sunday caused a power surge and smoke, triggering an emergency shutdown and forcing the staff to lower output from two of the reactors.
Kremlin spokesman Dmitry Peskov warned that the Ukrainian shelling of the plant is "fraught with catastrophic consequences for vast territories, for the entire Europe,” while the Russian Foreign Ministry has accused Ukraine of “taking the entire Europe hostage.”
Ukrainian officials countered by accusing Russian forces of planting explosives at the plant in preparation for an expected Ukrainian counteroffensive in the region. They also have accused Russia of launching attacks from the plant using Ukrainian workers there as human shields and shelling the place themselves.
Ukrainian President Volodymyr Zelenskyy said that the Russian shelling and mining of the plant amount to “nuclear blackmail.”
Zaporizhzhia Gov. Oleksandr Starukh said that while the reactors are well protected by their thick concrete containment domes, it is impossible to guarantee their safe operation because of the Russian troops' presence. He noted, too, that the storage sites at the plant for spent nuclear fuel are not as well protected as the reactors.
Mark Wenman, a nuclear expert at London’s Imperial College, said the plant’s reactors are designed “to protect against natural disasters and or man-made incidents such as aircraft crashes or reactor accidents.”
“I do not believe there would be a high probability of a breach of the containment building even if it was accidentally struck by an explosive shell, and even less likely the reactor itself could be damaged by such,” he said. He added that the spent fuel is also stored in "very robust steel and concrete containers that are designed to withstand very high-energy impacts.”
CALLS FOR INTERNATIONAL MONITORING
Rafael Mariano Grossi, director-general of the United Nations' nuclear watchdog, the International Atomic Energy Agency, told The Associated Press last week that the situation surrounding the Zaporizhzhia plant “is completely out of control,” and he issued an urgent plea to Russia and Ukraine to allow experts to visit the complex to stabilize matters and avoid a nuclear accident.
“Every principle of nuclear safety has been violated” at the plant, Grossi said. “What is at stake is extremely serious and extremely grave and dangerous.”
Grossi said the supply chain of equipment and spare parts has been interrupted, “so we are not sure the plant is getting all it needs.” He noted that the IAEA also needs to perform highly important inspections to ensure that nuclear material is being safeguarded.
Grossi added that there have been instances of friction and reports of violence between the Russians and the Ukrainian staff.
“When you put this together, you have a catalog of things that should never be happening in any nuclear facility,” Grossi said.
RUSSIA AND UKRAINE CLASH OVER IAEA VISIT
The IAEA has sought in vain to send an inspection team to the plant for months.
Moscow has said it welcomes a visit to the plant by the IAEA, but it is unclear whether it is ready to actually help arrange such a trip.
Ukraine previously opposed Grossi's visit to the site for as long as it remains under Moscow's control, demanding the Russian military withdraw.
This week, however, Ukrainian officials appeared to warm up to such a trip, with Ukraine’s ombudsman, Dmytro Lubinets, urging the U.N. and IAEA to send a delegation to help “completely demilitarize the territory” and provide security guarantees to plant employees.
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